Merge pull request #10769 from ipython/auto-backport-of-pr-10756

Backport PR  #10756 on branch 5.x

IPython/core/pylabtools.py

@@ -17,16 +17,17 b" backends = {'tk': 'TkAgg',"
             'gtk': 'GTKAgg',
             'gtk3': 'GTK3Agg',
             'wx': 'WXAgg',
-            'qt': 'Qt4Agg', # qt3 not supported
             'qt4': 'Qt4Agg',
             'qt5': 'Qt5Agg',
+            'qt': 'Qt5Agg',
             'osx': 'MacOSX',
             'nbagg': 'nbAgg',
             'notebook': 'nbAgg',
             'agg': 'agg',
             'inline': 'module://ipykernel.pylab.backend_inline',
             'ipympl': 'module://ipympl.backend_nbagg',
-}
+            'widget': 'module://ipympl.backend_nbagg',
+            }
 
 # We also need a reverse backends2guis mapping that will properly choose which
 # GUI support to activate based on the desired matplotlib backend.  For the